Density of a gas is found to be 5.46 g/dm³ at 27 °C at 2 bar pressure. What will be its density at STP?

The mass of an electron is 9.1 × 10^–31 kg. If its K.E. is 3.0 × 10^–25 J, calculate its wavelength.

Calculate the amount of carbon dioxide that could be produced when

(i) 1 mole of carbon is burnt in air.

(ii) 1 mole of carbon is burnt in 16 g of dioxygen.

(iii) 2 moles of carbon are burnt in 16 g of dioxygen.

Calculate the wavelength of an electron moving with a velocity of 2.05 × 10⁷ ms^–1.

Balance the following redox reactions by ion – electron method :

(a) MnO₄ ^– (aq) + I ^– (aq) → MnO_{2 (s)} + I_2(s) (in basic medium)

(b) MnO₄ ^– (aq) + SO_{2 (g)} → Mn²⁺ (aq) + HSO₄^– (aq) (in acidic solution)

(c) H₂O_{2 (aq)} + Fe ²⁺ (aq) → Fe³⁺ (aq) + H₂O (l) (in acidic solution)

(d) Cr₂O₇ ^2– + SO_2(g) → Cr³⁺ _(aq) + SO₄^2– (aq) (in acidic solution)

In a process, 701 J of heat is absorbed by a system and 394 J ofwork is done by the system. What is the change in internal energy for the process?

What will be the minimum pressure required to compress 500 dm³ of air at 1 bar to 200 dm³ at 30°C?

In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.

(i) 300 atoms of A + 200 molecules of B

(ii) 2 mol A + 3 mol B

(iii) 100 atoms of A + 100 molecules of B

(iv) 5 mol A + 2.5 mol B

(v) 2.5 mol A + 5 mol B

At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

Which one of the following will have largest number of atoms?

(i) 1 g Au (s)

(ii) 1 g Na (s)

(iii) 1 g Li (s)

(iv) 1 g of Cl2(g)

What is meant by the term bond order? Calculate the bond order of: N₂, O₂,O₂⁺,and O₂^-.

Write down the products of ozonolysis of 1,2-dimethylbenzene (o-xylene). How does the result support Kekule structure for benzene?

Explain tropospheric pollution in 100 words.

How much time would it take to distribute one Avogadro number of wheat grains, if 10¹⁰ grains are distributed each second?

The first ionization enthalpy values (in kJmol–1) of group 13 elements are :
B Al Ga In Tl
801 577 579 558 589
How would you explain this deviation from the general trend?

Complete the following chemical reactions.

(i) PbS_(s)  +  H₂O_2(aq)   → 

(ii)  MnO^-_4(aq)  +  H₂O_2(aq)   →

(iii)  CaO_(s)  +  H₂O_(g)  →

(iv) AlCl_3(g)   +   H₂O_(I)   →

(v) Ca₃N_2(s)   +  H₂O_(I)  →

Classify the above into (a) hydrolysis, (b) redox and (c) hydration reactions.

If the velocity of the electron in Bohr’s first orbit is 2.19 × 10⁶ ms^–1, calculate the de Broglie wavelength associated with it.

Why does boron trifluoride behave as a Lewis acid?

Calculate the standard enthalpy of formation of CH₃OH(l) from the following data:

CH₃OH (l) + 3/2 O₂(g) → CO₂(g) + 2H₂O(l) ;   Δ_rH⁰  = –726 kJ mol^–1

C(g) + O₂(g) → CO₂(g) ;    Δ_cH⁰ = –393 kJ mol^–1

H₂(g) + 1/2 O₂(g) → H₂O(l) ;    Δ_fH⁰ = –286 kJ mol^–1.

Prefixes Multiples
(i) micro 10⁶
(ii) deca 10⁹
(iii) mega 10^–6
(iv) giga 10^–15
(v) femto 10

Write the important conditions required for the linear combination of atomic orbitals to form molecular orbitals.